Plant for producing fiberboard plates and the like



July 2 1, 1970 R; HESCH PL'ANT.FOR PRODUCING FIBERBOARD PL'ATESgAND THE LIKE Filed Aug. 28. 1967 Rolf Hesch I N VEN TOR.

United States Patent 3,521,323 PLANT FOR PRODUCING FIBERBOARD PLATES AND THE LIKE Rolf Hesch, Huls, Krefeld, Germany, assignor to G.

Siempelkamp & Co., Krefeld, Germany, a corporation of Germany Filed Aug. 28, 1967, Ser. No. 663,576 Claims priority, application Germany, Aug. 27, 1966,

Im. or. am 3/134,- B30b 9/28 US. Cl. 18-4 Claims ABSTRACT OF THE DISCLOSURE Several support sheets may be superposed for alternate charging from a common hopper, one sheet receiving a charge while another feeds the prepress.

My present invention relates to a plant for the production of plates of fiberboard or pressed-board type from cellulosic or other particulate material, such as sawdust, wood chips and/or fibers, this material being deposited with or without a hardenable binder and in one or more strata on a movable support for delivery to a heated press adapted to consolidate it into simple or laminated plates. Such systems have been disclosed, for example, in US. Pat. Nos. 3,050,200 and 3,077,271 issued to Eugen Siempelkamp.

It is frequently desirable, particularly if the final press is of the multilevel type, to dispose a prepress between this final press and the dispenser for the loose starting material in order that the initial pile of this material may reach the final press in a somewhat compacted form, thus allowing for a reduced spacing between the heated press platens. Heretofore, the feeding of the loosely piled chips, fibers or the like to the prepress was usually accomplished with the aid of rectangular frames designed to hold the material together during transportation and to define the shape of the precompressed cake. The removal of such frames from the conveyor system after precompression, and the subsequent redeposition of the frames on the movable support, leading to the prepress, required relatively complex machinery.

The general object of my present invention is to provide means in such system for feeding loosely piled particulate material of the character described to a prepress in a manner eliminating the need for such frames without endangering the continuity of the precompressed cake.

A more particular object of this invention is to provide means in such system for rapidly delivering a succession of piles of such material to a prepress.

According to an important feature of my invention, the foregoing objects are realized by the provision of at least one flexible support sheet for the starting material this support sheet being anchored at one end to a windup mechanism in the immediate vicinity of the prepress whereby the sheet may be coiled into a roll in the manner of a conventional window shade; a sheet of this type, consisting of a low-friction thermoplastic material, such as Teflon (polytetrafluoroethylene), has been described in commonly assigned application Ser. No. 508,653 filed Nov. 19, 1965 by Kurt Loewenfeld and Wolfgang Reiners, now Pat. No. 3,368,242. A tensioning device is anchored to the sheet at a location remote from the windup mechanism for the purpose of extending the sheet underneath a hopper adapted to charge the sheet with a pile of starting material. The windup mechanism thereupon operates to retract the sheet from the vicinity of the hopper and to transport the pile to the entrance of the prepress.

Advantageously, in accordance with another feature of my invention, the prepress includes an endless band or belt encircling its bed and driven substantially in synchronism with the windup mechanism of the support sheet to receive the pile of starting material from the sheet and to transfer it intact to the prepress for compaction therein, this arrangement eliminating the stresses which might otherwise result upon a pushing of the pile by the support sheet onto the stationary prepress bed. Means may be provided at or beyond the prepress for trimming the edges of the emerging cake.

According to a more specific feature of my invention two or more support sheets of the aforedes'cribed character are provided in vertically spaced relationship and are arranged for alternate charging by a common hopper, the charging of one sheet coinciding with the delivery of the charge of another sheet to the prepress. This arrangement considerably speeds up the loading of the prepress and, therefore, the production of fiberboard or similar plates.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a somewhat diagrammatic side-elevational View, partly in section, of a plant embodying my improved transport means;

FIG. 2 is a view similar to FIG. 1, illustrating an alternate position of the transport means; and

FIG. 3 is a top plan view of the transport means taken on the line IHIII of FIG. 1.

The plant shown in the drawing comprises a dispenser 1 which, as shown, may consist of several hoppers 1a, 1b, designed to deposit several layers of fibrous and/or granular cellulosic or other polymeric starting material, possibly together with a thermally curable binder, on a transport system comprising a pair of vertically spaced sheets 2', 2" of low-friction thermoplastic material, preferably Teflon, adapted to be wound up on respective shafts 21, 21 which are journaled in a frame 22. The sheets 2', 2" terminate in cross-bars 23, 23 to which tensioning cords 24', 24" are anchored. The other ends of these cords are attached to respective capstans 25', 25" which can be alternately driven, by suitable transmissions not shown, to wind up the cords 24' or 24" against the force of loading springs (likewise not shown) that are coupled with the shafts 21', 21" so as to bias the latter counterclockwise as viewed in FIGS. 1 and 2, thereby tending to coil the sheets 2', 2" around these shafts in a manner known from conventional window shades. Thus, FIGS. 1 and 3 show the upper sheet 2' retracted by its loading spring and partly wrapped around the shaft 21, the other sheet 2" being fully extended by its tensioning cords 24" which are almost entirely wound around capstan 25"; FIG. 2 illustrates the reverse position, with sheet 2' extended and sheet 2" withdrawn.

A prepress 3 has an entrance end positioned close to the frame 22 which may be selectively lowered and raised, e.g. by a hydraulic cylinder 26, to align either the sheet 2' or the sheet 2" with that entrance end. An endless belt 11 of pressure-resistant material, e.g. steel, surrounds the bed 31 of press 3 and terminates close to the forward end of sheet 2' or 2" so as to be able to receive from it a pile 7 or 7" of deposited material respectively carried by these sheets and entrained by their end bars 23', 23". The operating speed of conveyor belt 11 is chosen to be substantially identical with that of the sheet 2' or 2" in the terminal phase of its forward motion so that the charge 7 or 7" can be transferred to the press 3 without disruption, each sheet being unwound after such transfer from its shaft 21' or 21" by the associated capstan 25 or 25" as described above. With the pile 7 or 7" fully inside the press, belt 11 is halted to allow this pile to be compressed into a relatively firm cake 7a which is thereafter transported by one or more further conveyors 9 to an elevatable stacking rack 4 (of the type disclosed in the aforementioned Siempelkamp Pat. 3,077,271) for delivery to the several levels of a final press 5. A stacked output conveyor has been shown at 12.

A vertically movable cutting frame 13 may be lowered onto conveyor 9 to trim the edges of cake 7a, with temporary halting of that conveyor or with the frame 13 moving at the same forward speed as the conveyor.

Because of the relative length of the transport path from dispenser 1 to prepress 3, the vertical displacement of frame 22 to align the two sheets 2', 2" with the belt 11 involves only a slight tilting of these sheets without any resulting shifting of the pile 7 or 7" thereon.

It will be apparent that, by the arrangement described, either of the sheets 2', 2" can be charged by the dispenser 1 while the other sheet delivers the charge to the prepress 3. If desired, the number of superposed transfer sheets, operating at staggered intervals, may also be increased.

I claim:

1. A plant for the production of pressed-board plates, comprising hopper means for dispensing a particulate starting material to be compressed into such plates, a final press provided with heating means, a prepress disposed between said hopper means and said final press, and transport means for delivering a pile of said starting material to said prepress for precompression therein to form a cake and delivering said cake to said final press for compression and solidification to form a plate, said transport means including flexible support means reciprocable between said hopper means and said prepress and positionable for receiving therefrom a pile of said material to be delivered to said prepress, the latter being provided with a bed and with an endless conveyor encircling said bed, said conveyor being substantially synchronized with said transport means for receiving said pile from said sheet.

2. A plant as defined in claim 1, further comprising trimmer means for said cake ahead of said final press.

3. A plant as defined in claim 1 wherein said support means includes a pair of flexible sheets alternately reciprocable between said hopper means and said prepress.

4. A plant as defined in claim 3 wherein said support sheets are provided with vertically separated guide paths,

5. A plant as defined in claim 1 wherein said support means comprises a sheet of polytetrafluoroethylene.

References Cited UNITED STATES PATENTS 2,321,252 6/1943 Sayre 1816 2,618,813 11/1952 Patton et a1. 18-4 X 3,125,947 3/1964 Hubin 18-16 X 3,353,236 11/1967 Stedman 18-4 X 3,368,242 2/1968 Loewenfcld et a1. 18-16 X WILBUR L. McBAY, Primary Examiner US. Cl. X.R. 185, 16; 264-120 

